(function ($) {
    $.fn.extend({
        //插件名称 - 
    	infiniteCarousel: function () {

    	    function repeat(str, num) {
    	        return new Array( num + 1 ).join( str );
    	    };
    	    
    	    return this.each(function () {
    	        var $wrapper = $('> div', this).css('overflow', 'hidden'),
    	            $slider = $wrapper.find('> ul'),
    	            $items = $slider.find('> li'),
    	            $single = $items.filter(':first'),
    	            
    	            singleWidth = $single.outerWidth(), 
    	            visible = Math.ceil($wrapper.innerWidth() / singleWidth), // note: doesn't include padding or border
    	            currentPage = 1,
    	            pages = Math.ceil($items.length / visible);            


    	        // 1. Pad so that 'visible' number will always be seen, otherwise create empty items
    	        if (($items.length % visible) != 0) {
    	            $slider.append(repeat('<li class="empty" />', visible - ($items.length % visible)));
    	            $items = $slider.find('> li');
    	        }

    	        // 2. Top and tail the list with 'visible' number of items, top has the last section, and tail has the first
    	        $items.filter(':first').before($items.slice(- visible).clone().addClass('cloned'));
    	       // $items.filter(':last').after($items.slice(0, visible).clone().addClass('cloned'));
    	        $items = $slider.find('> li'); // reselect
    	        
    	        // 3. Set the left position to the first 'real' item
    	        $wrapper.scrollLeft(singleWidth * visible);
    	        
    	        // 4. paging function
    	        function gotoPage(page) {
    	            var dir = page < currentPage ? -1 : 1,
    	                n = Math.abs(currentPage - page),
    	                left = singleWidth * dir * visible * n;
    	            $wrapper.filter(':not(:animated)').animate({
    	                scrollLeft : '+=' + left
    	            }, 500, function () {
    	                if (page == 0) {
    	                    $wrapper.scrollLeft(singleWidth * visible * pages);
    	                    page = pages;
    	                } else if (page > pages) {
    	                    $wrapper.scrollLeft(singleWidth * visible);
    	                    // reset back to start position
    	                    page = 1;
    	                } 

    	                currentPage = page;
    	            });                
    	            
    	            return false;
    	        }
    	        
    	        // $wrapper.after('<a class="spec-left">&lt;</a><a class="spec-right">&gt;</a>');
    	        
    	        // 5. Bind to the forward and back buttons
    	        $('.back', this).click(function () {
    	            return gotoPage(currentPage - 1);                
    	        });
    	        
    	        $('.forward', this).click(function () {
    	            return gotoPage(currentPage + 1);
    	        });
    	        
    	        // create a public interface to move to a specific page
    	        $(this).bind('goto', function (event, page) {
    	            gotoPage(page);
    	        });
    	    });  
        }
    });
})(jQuery);